The oceans present a rather constant environment for the life it holds. While temperature and salinity and other environmental factors may vary from place to place, in any given region of the ocean those environmental factors remain quite constant. As a consequence, the creatures of the sea have generally not developed adaptive mechanisms. That is true both for invertebrates and for fish, although fish can often tolerate more change in environmental conditions than can the invertebrates.
Their inability to adapt to changed conditions has made it very difficult to preserve sea life in aquariums. Attempts to reproduce the environment of the ocean in small aquariums, less than several thousands of gallons in size, have met with failure because it is not practical to deal with excretions as they are in the sea. Those excretions are largely ammonia which is highly toxic both to fish and to invertebrates. The only practical way that has been discovered to eliminate the ammonia in aquariums is to rely upon reduction to nitrate form by bacterial action coupled with periodic replacement of part of the aquarium water. Typically, 25 percent of the aquarium water is replaced monthly. Moreover, it is necessary to remove a major portion of unused food, especially the protein matter, if water quality is to be maintained in a non-toxic condition.
Most salt water fish can live for an indefinite period in water that is subjected to that kind of a purification program. Even invertebrates, which as a class are much less adaptable than fish, can live for long periods of time in water that is treated in that fashion and which does not contain fish. Survival of the invertebrates is much less certain when they are combined with fish. The chemical balance is so delicate that introduction of even one additional fish in a forty gallon sized aquarium may result in the death of some invertebrates before the additional ammonia discharge can be accommodated by an increase in bacterial action.
Since it is usually not possible to furnish the inhabitants of an aquarium with the kind of food that they lived on in the sea prior to being captured, it is necessary to provide a substitute food, and that substitute must be one that will provide adequate nourishment for the creatures without upsetting the ecological balance in their synthesized environment. To provide a food that can be accommodated by that ecological system is one of the objects of the invention.
The filter feeders, the tube worms, anemones, corals, and the like, subsist on plankton in their natural environment. No practical means has been found to supply plankton for smaller aquariums. The problem is to find a substitute capable of adequately nourishing the filter feeders and the fish, too, if possible. The substitute must have a mechanical form which permits its being eaten or filtered by both kinds of creatures and it must be compatable with aquarium ecology. While not essential, it is very desirable that the food be such that it is visible when placed in the aquarium to enable a determination that the food actually has reached the filter feeders.
The synthesized environment sometimes includes medicinal substances introduced to treat ailments suffered by the fish. In general, salt water invertebrates are unable to tolerate those medicines, so they, or the fish, must be removed to a hospital tank before the fish are treated. The food provided by the invention does not overcome that problem, but it does have the advantage that it does not appear to affect the action of most of the medicinal substances that are currently employed for treating fish ailments.
The problem of maintaining an ecological balance is coupled with the mechanical problem of getting food to the filter feeders. The filter feeders are generally located at the bottom of the aquarium, whereas the food must be introduced from the top of the aquarium.